Obesity is a major health concern in the United States as well as other western countries. A significant portion of the population is overweight with the number increasing every year. Obesity is one of the leading causes of preventable death. Obesity is associated with several co-morbidities that affect almost every body system. Some of these co-morbidities include: hypertension, heart disease, stroke, high cholesterol, diabetes, coronary disease, breathing disorders, sleep apnea, cancer, gallstones, and musculoskeletal problems. An obese patient is also at increased risk of developing Type II diabetes.
Multiple factors contribute to obesity, including physical inactivity and overeating. Existing therapies include diet, exercise, appetite suppressive drugs, metabolism enhancing drugs, surgical restriction of the gastric tract, and surgical modification of the gastric tract. These therapies may result in little or no weight loss up to weight loss of nearly 50% of initial body weight.
Natural feedback mechanisms, such as the normal sensation of fullness following a meal, may be insufficient for a patient to regulate his own behavior. In addition, natural feedback mechanisms may be inadequate to control a patient's behavior. An obese patient, for example, may continue to consume food after being full because of a delay between onset of fullness and the onset of the sensation of fullness.
Gastroparesis is an adverse medical condition in which normal gastric motor function is impaired. Gastroparesis is also called delayed gastric emptying as the stomach takes too long to empty its contents. Typically, gastroparesis results from muscles of the stomach and intestines not working normally, and movement of food through the stomach slows or stops. Patients with gastroparesis typically exhibit symptoms of nausea and/or vomiting and gastric discomfort. They may complain of bloating or a premature or extended feeling of fullness (satiety). The symptoms of gastroparesis are the result of reduced gastric motility. Gastroparesis generally results in patients reducing food intake and subsequently losing weight.
Electric stimulation of the gastrointestinal tract has been proposed as a mechanism for treating morbid obesity. Table 1 below lists examples of documents that disclose techniques for electric stimulation of the gastrointestinal tract for the treatment of various conditions including obesity. These disclosures suggest that disruption in the normal stomach motility which may then cause symptoms of gastroparesis may be useful in the treatment of obesity.
Experimental results suggest that electric stimulation of the gastrointestinal tract that results in disruption of normal stomach motility requires simulation pulses approximately equal to a normal human stomach's gastric slow wave of approximately 3 cycles per minute (cpm). A gastric slow wave corresponds to a contraction propagation frequency in a human stomach used to cause movement of contents within the gastrointestinal tract.
TABLE 1Pat. No.InventorsTitle20020072780FoleyMethod and apparatus for intentionalimpairment of gastric motility and /orefficiency by triggered electricalstimulation of the gastrointestinal tractwith respect to the intrinsic gastricelectrical activity6,327,503FamiloniMethod and apparatus for sensing andstimulating gastrointestinal tracton-demand5,836,994BourgeoisMethod and apparatus for electricalstimulation of the gastrointestinal tract5,995,872BourgeoisMethod and apparatus for electricalstimulation of the gastrointestinal tract6,091,992BourgeoisMethod and apparatus for electricalstimulation of the gastrointestinal tract6,104,955BourgeoisMethod and apparatus for electricalstimulation of the gastrointestinal tract6,115,635BourgeoisMethod and apparatus for electricalstimulation of the gastrointestinal tract6,216,039BourgeoisMethod and apparatus for treatingirregular gastric rhythms5,423,872CigianaProcess and Device for Treating Obesityand Syndromes Relates to MotorDisorders of the Stomach of a Patient6,542,776Gordon et al.Gastric Stimulator and Method forInstalling6,606,523JenkinsGastric Stimulator Apparatus and Methodfor Installing6,615,084CigianaProcess for Electrostimulation Treatmentof Morbid Obesity
All documents listed in Table 1 above are hereby incorporated by reference herein in their respective entireties. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and Claims set forth below, many of the devices and methods disclosed in the patents of Table 1 may be modified advantageously by using the techniques of the present invention.